The present invention concerns headphones or headsets, particularly battery-powered headsets with automatic noise-reduction circuitry.
Headsets typically include two earcups which are worn over ears of users to enhance or protect their hearing. For example, many workers wear headsets to protect their hearing from loud persistent noises, such as airplane engines and construction equipment. These headsets are generally passive or active. Those that are passive only cover the ears with a sound-muffling material, whereas those that are active include ear speakers and automatic noise-reduction (ANR) circuitry. The noise-reduction circuitry automatically cancels or suppresses certain types of loud persistent noises. Active headsets are often battery-powered and include an on-off switch to turn them on and off.
One problem with battery-powered headsets, particularly those with automatic noise-reduction circuitry, concerns battery life. Workers having these headsets generally put on and take off their headphones many times throughout a workday, often forgetting to turn them off and wasting costly battery life. Moreover, for those headsets that are used infrequently with long storage times between uses, the turn-off problem is worse not only because their batteries are more apt to die, but fresh batteries are too often unavailable or inconvenient to obtain.
To address this and other needs, the inventor devised active headsets with automatic turn-on and/or turn-off circuits and related mode-control methods for active headsets. One exemplary embodiment senses a condition of the headsets, for example, the light, pressure, or temperature within one earcup, and then turns the headset on or off in response to the sensed condition. Other embodiments that include automatic noise-reduction (ANR) circuitry use an ANR driver to sense engagement of an earcup with a user""s head and an ANR microphone to sense disengagement of the earcup from the user""s head.